(a) Field of the Invention
The present invention relates to a technology for fabricating a plurality of substrates using one mother glass, and more particularly, to a technology for uniformly applying a dielectric layer on each of a plurality of substrates fabricated from one mother glass.
(b) Description of the Related Art
A plasma display panel (PDP) is a device for displaying images using a gas discharge phenomenon. PDP has excellent benefits in multiple display characteristics, such as brightness, contrast, after-image, and viewing angle, over other display device types. A PDP is formed by combining a front plate and a rear plate together. The front plate is created by forming a display electrode and a dielectric layer on a front substrate. The rear plate is created by forming an address electrode, a dielectric layer, barrier ribs partitioning discharge cells, and a phosphor layer on a rear substrate.
A pair of display electrodes are formed on the front substrate corresponding to each discharge cell. The display electrodes are covered with the dielectric layer that protects the display electrodes and induces charged particles. Similarly, an address electrode is formed on the rear substrate corresponding to each discharge cell. The address electrode is covered with the dielectric layer, thereby protecting the address electrode.
Such dielectric layers covering the display electrodes and the address electrode are formed through various methods such as a printing method, dry film method, or coating method, after forming the display electrodes and the address electrode respectively on the front substrate and the rear substrate. The printing method forms the dielectric layer using a printing device. The dry film method forms the dielectric layer by laminating a dry film resistor (DFR) and then baking it. The coating method forms the dielectric layer by directly spraying a dielectric material onto the electrodes using a coating device.
The coating method forms the dielectric layer by spraying dielectric material paste using a coating device, as a result, the thickness of the dielectric layer may be relatively thin, during an early stage of injection, because an amount of the sprayed dielectric material paste may be relatively small during that period due to the viscosity of the paste and the friction between the paste and an inner surface of a nozzle of the coating device. On the other hand, a thickness of the dielectric layer may be relatively thick, at a region where the injection ceases, because an amount of the sprayed dielectric material paste may be relatively great in that region. Consequently, it is difficult to form a dielectric layer having a uniform thickness on the substrate. Furthermore, such a problem becomes much more serious when a plurality of substrates are fabricated using one mother glass.
In the case where a dielectric layer is formed on one mother glass that will be divided into a plurality of substrates, the dielectric layers are formed by intermittently spraying dielectric material paste for respective substrates. That is, because spraying of dielectric material paste is stopped at a region between neighboring substrates, it is difficult to form a dielectric layer with a uniform thickness over the whole substrate.